Power operated bleacher



4, 1964 w. J. HARMS POWER OPERATED BLEACHER 5 Sheets-Sheet 1 Filed Oct. 6, 1960 INVENTOR.

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Aug. 4, 1964 w. J. HARMS POWER OPERATED BLEACHER 5 Sheets-Sheet 3 Filed 001;. 6. 1960 Aug. 4, 1964 W. J. HARMS POWER OPERATED BLEACHER 5 Sheets-Sheet 4 Filed Oct. 6, 1960 Aug. 4, 1964 w. J. HARMS POWER OPERATED BLEACHER 5 Sheets-Sheet 5 Filed Oct. 6, 1960 II II l ly- United States Patent ice 3,142,871 PGWER OPERATED BLEACHER William J. Harms, Kalamazoo, Mich, assignor to Brunswick Corporation, a corporation of Delaware Filed Oct. 6, 1960, Ser. No. 60,857 20 Claims. (Cl. 201.126)

This invention relates to extensible and retractable bleachers, and particularly to a power operable bleacher.

It is a general object of the invention to provide a new and improved bleacher construction of the character mentioned.

Another object is to provide a new and improved foldable bleacher including remotely controllable power operated means for extending the bleacher from a folded condition to an extended usable condition.

A further object is to provide a new and improved bleacher construction of the type mentioned in the preceding paragraph, including a plurality of upright frames, one of which is stationary and the remainder of which are movable between extended and retracted positions relative to the stationary frame, together with a reciprocating pusher having a yieldably mounted pawl engageable with successive frames as the pusher is reciprocated, thereby to push the frontmost frame and then the succeeding rearwardly disposed frames to extended positions relative to the stationary frame.

Another object is to provide a new and improved bleacher construction of the type described in the preceding paragraph, including means for successively holding succeeding frames stationary while preceding, forwardly disposed frames are pushed toward extended positions.

It is also an object of the invention to provide a new and improved bleacher operator including a reciprocable pusher, a cable having a midportion secured to the pusher, means for positioning opposite end portions of the cable so that when these are alternately pulled in opposite directions, the pusher is reciprocated back and forth, together with means for alternately pulling opposite ends of the cable for operating the pusher.

A further object is to provide a new and improved bleacher operator of the type described in the preceding paragraph, including a rocker member, means connecting opposite ends of the aforementioned cable to the rocker member, and an eccentric means for rocking the rocker member back and forth to reciprocate the pusher.

A further object is to provide a new and improved bleacher construction including a cable system attached to the frontmost bleacher frame for folding the bleacher, together with a common drive means for operating the bleacher folding means and the bleacher extending means.

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is an end elevational view of a fragmentary portion of a foldable bleacher adapted to include a power operator mechanism embodying the principles of the present invention;

FIG. 2 is a fragmentary perspective View illustrating the application of a power operator means embodying the principles of the present invention, to a bleacher construction of the type illustrated in FIG. 1;

FIG. 3 is a top plan view of a bleacher extending mechanism embodying the principles of the present invention;

FIG. 4 is a side elevational view of the mechanism illustrated in FIG. 3;

FIG. 5 is a sectional view taken at about the line 55 of FIG. 4;

FIG. 5a is a fragmentary top plan view illustrating a limit switch;

3,142,871 Patented Aug. 4, 1964 FIG. 6 is an enlarged fragmentary sectional view taken at about the line 66 of FIG. 3;

FIG. 7 is an enlarged fragmentary sectional view taken at about the line 7--7 of FIG. 3;

FIG. 8 is an enlarged gragmentary sectional view taken at about the line 88 of FIG. 3;

FIG. 9 is an enlarged fragmentary sectional view taken at about the line 99 of FIG. 3;

FIG. 10 is a fragmentary rear elevational View of the bleacher construction illustrated in FIG. 2;

FIG. 11 is a bottom plan view of the structure illustrated in FIG. 10;

FIG. 12 is an enlarged fragmentary front elevational view of the power unit illustrated in FIG. 10, showing particularly the rocker member to which cables are attached for operating one or more reciprocating pushers for extending the bleacher;

FIG. 13 is a horizontal sectional view of the construction illustrated in FIG. 12;

FIG. 14 is a sectional view taken at about the line 1414 of FIG. 12;

FIG. 15 is a fragmentary sectional view taken at about the line 15-15 of FIG. 13; and

FIG. 16 is a top plan view of the power unit.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms, and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Referring now to the drawings in more detail, power operator mechanism embodying the principles of the present invention is adapted for use in a bleacher construction of the type illustrated in the Lappin et al. Patent 2,815,541 of December 10, 1957. A bleacher of this type is illustrated in FIG. 1 herein, and provides a plurality of rows of spectator seating of gradually decreasing height from a stationary rearmost row to a lowermost front row where seated spectators may rest their feet on the fioor of a gymnasium or the like in which the bleacher is installed. As seen best in FIGS. 1 and 2, the rows of seating are provided by a plurality of upright frames of progressively lesser height from rear to front and each including a plurality of laterally aligned upright members or posts 20, only one of which in each row is visible in the end elevation of FIG. 1, the uprights of each row being rigidly interconnected by suitable brace means, such as diagonal braces 21, also illustrated in the aforementioned patent, and suitable connecting crosspieces preferably in the form of angle irons as shown at 22. In FIG. 1, five such upright frames of gradually decreasing height are illustrated in a fragmentary showing of a bleacher construction which includes eight such upright frames, three being omitted by virtue of the broken away portion of the figure. Obviously, the bleacher may include any number of such uprights within reason, and there may be as many as 18.

The upright tubular members 20 of the rearmost frame are secured at the lower end to a floor or other supporting surface by any suitable means such as a bracket 23, and at the upper end may be secured to a vertical wall or the like by suitable means such as a bracket 24. Tubular members 20 of the intermediate frames between the rearmost frame and the frontmost frame are movably supported on the floor or the like by rollers as at 25, while the tubular members 20 of the frontmost frame are supported by a roller as at 26 and rollers as at 27 and 28 carried by a U-shaped bracket 29 suitably secured to the frame.

Fixed to the upper ends of the upright members 2% in each row except the frontmost are brackets 35 each of which has an arcuate slot as at 35a, and fixed to the end uprights in the frontmost row are brackets 36. Secured to the upper surfaces of the brackets in each row are seatboards 37 which extend longitudinally for the length of the frames.

Secured to the seatboard brackets 36 of the frontmost bleacher frame and extending downwardly therefrom and longitudinally for the length of the frame is a two-sectioned kickboard including an upper portion 39 and a lower portion 4t) hingedly connected to the upper portion.

Adjacent upright frames are interconnected by associated foldable linkage means so that the movable frames are adapted for movement between extended positions, as illustrated in the drawings herein, and retracted positions relative to the stationary rearmost frame. It will be understood that the bleacher is to be unfolded or extended for use in supporting spectators or the like, and folded or retracted for compact storage when not in use. Foldable linkages of the type mentioned are provided at each end of the bleacher, but in order to simplify the drawings only one end of the bleacher is shown in FIG. 1 and described herein. It will be understood that the foldable linkages at the opposite end are substantially identical to those shown and described.

The linkage means foldably interconnecting the two frontmost frames includes two vertically spaced links 40 and 41 each having one end pivotally connected to the tubular upright 20 of the second frame and extending forwardly therefrom. Secured to the upright 20 of the frontrnost frame is a bracket 42 extending upwardly and rearwardly. A footboard supporting bar 44 is pivotally connected to the bracket 42 and, at 45, to the forward end of link 40. A link 47 is pivotally connected to link 41 at 43 and at 49 to bracket 29. Extending vertically between the connections 45 and 48 and pivotally mounted therebetween is a vertical link 51. A footboard 53 is secured to footboard supporting bar 44 and extends longitudinally for the length of the bleacher.

A link 55 has one end pivotally connected at 56 to link 49 and has the other end pivotally connected at 58 to a skirtboard mounting means for the second frame from the front of the bleacher.

Movably carried in arcuate slots 35a of brackets 35 are a skirtboard bracket 60 and a plate 61, the plate and the bracket being connected together at 62 and 63. Pivotally connected at its upper end to bracket 69 and plate 61 is a link 65 having its lower end connected to the upper end of link 55. Secured to the skirtboard bracket 60 and extending longitudinally for the length of the bleacher is a skirtboard 6'7.

Foldable linkage means interconnecting each pair of rearwardly disposed frames each includes vertically spaced links 79 and 71, similar to links 46 and 41 previously described, each having a rear end pivoted to the rearwardly disposed upright tubular member 20 and extending forwardly therefrom. Brackets 72 and 74 are secured to forwardly disposed uprights 20 in vertically spaced relation and pivotally carry respectively a rearwardly extending footboard supporting bar 75 and a bell crank member 76. The forward end of link 71 is pivotally connected to the rear end of bell crank member '76 as at 77, and the forward end of link 70 is connected to footboard supporting bar 75 as at 78. Extending vertically between the links 70 and 71 is a vertical link 80 pivotally connected at its lower end to link '71 and having at its upper end a vertical slot 81 providing a slidable and pivotal connection to link 70 at 82.

Fastened to footboard supporting bar 75 and extending longitudinally for the length of the bleacher is a footboard 84. Means are provided for stabilizing the bleacher when unfolded including bracket 72 which has an angle portion 72a operable to support the pivoted footboard supporting bar 75 when the latter is in horizontal position, thereby to positively prevent further downward movement of the board.

To aid in folding the bleacher, an angled bracket 86 provided on each of the links 41 and 71 is operable upon movement in an upward direction to engage arm 87 of the rearwardly disposed bell crank member 76 to pivotally move the bell crank in a clockwise direction and break the linkage connection at 77.

A link 55, similar to link 55, has its lower end pivotally connected to link 70 at the connection 82, and has its upper end connected to the skirtboard operating link 65.

When the bleacher is unfolded, that is, extended, as shown in the drawings, the foldable linkages interconnecting the frames are locked in the position shown. To fold the bleacher, the link connections at 45 and 48 must be broken or unlocked, either by raising the frontmost footboard 53 or by pulling the frontmost skirtboard 67 forwardly, or both. Normally, such an operation has been accomplished manually. After this, the frontrnost frame may be forced rearwardly and folding of the remaining frames and linkages follows automatically. During folding, the footboards 53 and 84 are pivoted forwardly and upwardly to substantially vertical positions, while the skirtboards are pivoted forwardly and upwardly to forwardly and downwardly inclined positions, as shown in the Lappin et al. patent referred to hereinabove. To unfold the bleacher, the frontmost frame is forced forwardly and the remaining frames follow.

In the past, bleachers of the type described hereinabove have most often been folded and unfolded manually by pushing and pulling on the frontmost bleacher frame. According to the present invention, a remotely controllable power operable mechanism is built into the bleacher for folding and unfolding the latter. The power operable means takes the form of a drive motor which may be an electric motor adapted to be operated from a control station conveniently located for access by the operator and connected for operation from the control station in one direction to extend and unfold the bleacher and in the opposite direction to fold and retract the bleacher. FIG. 2 illustrates the application of such a power operable mechanism to a bleacher of the type described hereinbefore. In this figure, portions of the bleacher have been omitted in order to more clearly illustrate the application of the control. For the purpose of illustration, portions of an 18 row bleacher have been shown in FIG. 2, but it will be understood that the power operable mechanism may be applied to a bleacher of almost any number of rows. As shown in FIG. 2, portions of row #1, row #7, row #8, row number #14 and row #18 have been referred to.

In order to unfold the folded bleacher by successively extending individual frames forwardly relative to the stationary rearmost row, a plurality of pusher units are provided. Preferably two such units are provided with each bleacher, regardless of the length, and in the bleacher illustrated in. FIG. 2, three such units are utilized, as at a, ltltlb and 1000. The pusher units each include a reciprocating pusher carrying a yieldable pusher pawl adapted for engagement with angle irons 22 associated with the upright frames. As the frontrnost bleacher frame normally does not include a suitably located angle iron as at 22, separate laterally spaced angle members are provided on the frontmost frame as at 102, laterally spaced in alignment with the pusher units, and suitably supported on the frontmost frame beneath the seatboard 37 as by framework 103. In order to provide for connection of the pusher unit to the rearmost bleacher frame, a transversely extending tubular beam member 1&4 of rectangular cross section is secured to the rearmost upright 20.

Referring particularly to FIGS. 3, 4 and 5, each pusher includes a stationary beam or bar having a flange 105 secured to the beam 184. Secured to the forward end of the beam 105 are a pair of laterally outwardly turned channel shaped guide members 108 Beneath the channel members 108 are a pair of outwardly facing angle members 109, secured together at the forward ends by a spacer member 110. The angle members 109 carry guide rollers 112 movable along the channels 108. Guided on the roller 112 is an outer frame including a pair of inwardly facing channel members 114 which carry at opposite ends depending legs 115 having lower ends supporting shafts 116 carrying floor engaging rollers 117. In this manner, the members 105 and 108 provide a stationary frame or guide, the members 109 provide an intermediate frame movable forwardly and rearwardly on the stationary frame, and the members 114 and their associated parts provide a floor supported frame reciprocable relative to the stationary frame and the intermediate frame. The last mentioned, outermost reciprocable frame is referred to herein as a pusher.

The pusher carries a pair of pusher pawls 120 pivotally mounted respectively on the channel members 114 as at 121. Each of the pusher pawls 120 is normally yieldably urged in a counterclockwise direction as viewed in FIG. 4 by means of a torsion spring 123 (see FIG. 9, also) coiled about the pivot axis and suitably anchored on the associated channel member 114 and the associated pawl 120. Each of the pawls 120 includes a forward end portion adapted to successively engage the bleacher angle irons 102 and 22 as the pusher is reciprocated thereby to successively push the frontmost bleacher frame and then the succeeding frames forwardly to extended positions. As the pusher is retracted toward the stationary rearmost frame, the pawls 12 0 are adapted to be depressed upon engagement with a succeeding angle iron 22 to pass therebeneath and subsequently rise to engage behind the next angle member. In order to depress the pawls 120 when the pusher is fully retracted and the bleacher is to be folded, so that the pawls do not prevent rearward movement of the angle members 22, the channel members 108 of the stationary frame are each provided with an out wardly extending plate member as at 130 disposed in the path of the associated pawls 120 (see FIG. 6 also).

When the bleacher is completely folded, the frontmost angle iron 102 is disposed at the position indicated in broken lines at 22a in FIG. 4. It is at this position that the pusher pawls 120 pick up or first engage the bleacher angle irons 102 and 22 to successively push the bleacher frames forwardly. As the frontmost bleacher angle iron 102 is pushed forwardly, as illustrated in FIG. 4, the angle iron 22 on the succeeding bleacher frame moves to the broken line position 22a and is held in such position until engaged by the pusher pawls 120 to be moved to the extended position. At the broken line position 22a, a holding means is provided to trap the succeding angle iron 22 to hold the latter against forward movement as the forwardly disposed bleacher linkage is unfolded, and to hold the member 22 against rearward movement as the pusher is retracted to pick up the succeeding angle iron. The trap means comprises a forwardly disposed rearwardly facing pawl 140 and a rearwardly disposed forwardly facing pawl 141.

The pawl 140 is pivotally mounted at 142 on one of the channel members 108 (see also FIG. 8), and urged in a clockwise direction as viewed in FIG. 4 by a torsion spring 143 coiled about the pivot axis and engaged respectively at opposite ends with the channel member 108 and the pawl 140. Upon retraction of the pusher toward the stationary rearmost frame, the plate 144 secured on one of the channel members 114 is adapted to engage the pawl 140 and depress the latter until such time as the pusher pawls 120 advance the succeeding angle member 22 beyond the retaining portion of the pawl 140.

The pawl 141 is pivotally mounted as at 146 on the opposite channel member 108 (see also FIG. 6) and urged in a counterclockwise direction as viewed in FIG. 4 by means of a torsion spring 147 coiled about the pivot axis and engaged respectively at opposite ends with channel member 108 and the pawl 141. As succeeding channel members 22 move forwardly toward the trap, they depress the pawl 141 to move into the trap, after which the pawl 141 permits rearward movement of the member 22.

It will be understood that with different bleachers including different numbers of upright frames or rows of seating, the position of the trap provided by the pawls and 141 will be at various distances from the stationary rearmost frame. This may be accomplished by mounting the channel members 108 at different positions longitudinally of the beam 105.

In order to depress the trap pawl 141 during the times when the bleacher is being folded, and the angle members 22 must pass rearwardly beyond the pawl 141, a release dog (see FIG. 7, also) is pivotally mounted on the stationary channel member 108 adjacent the pawl 141 on an axis 151. The dog 150 is urged in a counterclockwise direction as viewed in FIG. 4 by a coiled torsion spring 152 and engages a pin 153 on the pawl 141. In operation, as a bleacher angle iron 22 moves rearwardly towards the stationary rearmost frame, it engages the release dog 150 to depress the latter which thereupon depresses the pawl 141 through the pin 153 to allow passage of the angle iron rearwardly. As successive angle irons are moved forwardly of the bleacher, they engage the rear ends of the release dog and pivot the latter in a counterclockwise direction, permitting passage of the angle iron.

In order to reciprocate the pusher to advance successive frames on successive forward strokes, a drive means is connected with the pusher. Such drive means includes a cable including a lower reach 160a extending forwardly from the transverse beam 104 on the rearmost bleacher frame and about a pulley 161 on the stationary frame, to an upper reach 16% extending rearwardly from the pulley toward the beam 104. The pulley 161 is rotatably mounted on the pivot axis 142 for the trap pawl 140. As seen best in FIG. 8, such pivot axis extends transversely between the stationary outwardly turned channel members 108. The lower reach 160a of the cable is secured to a bracket 163 on the reciprocating pusher. As seen best in FIG. 5, the bracket 163 is secured to shaft 116 and to a spacer 164 extending between the depending legs 115. In operation, because the pulley 161 is disposed forwardly of the bracket 163, it will be understood that if the lower reach 1600: is pulled rearwardly, the reciprocable pusher will be pulled rearwardly by virtue of the fixed attachment of the cable to the pusher. On the other hand, if the upper reach 16012 is pulled rearwardly, the cable in passing about pulley 161 will pull the pusher forwardly.

As seen best in FIGS. 2, 10 and 11, cables 160 from each of the pusher units 100a, 100b, and 1000 extend rearwardly from the pusher units to the beam 104 on the rearmost bleacher frame. At the beam 104, the upper reaches 16% from each of the pusher units pass about pulleys 165a, 1651) and 1650, respectively, positioned on the upper side of the beam 104. The lower reaches 160a from each of the pusher units pass about pulleys on the lower side of the beam 104 respectively beneath pulleys 165a, 1651) and 165a as at 166a and 166b. From the pulleys 165 and 166, each of the reaches 160a and 16% is turned inwardly toward a power unit 170 mounted on the rearmost bleacher frame, and is then attached as at 171 to a power operable cable system for alternately pulling the opposite reaches 160a and 16017 to reciprocate the pusher.

The cable system last referred to includes a cable 175 having one end attached as at 176 to one end of an arcuate rim segment 177 of a rocker member described more in detail presently. From the attachment 176, the cable 175 passes under a portion of the segment 177, over a pulley 178, under a pulley 179, about a pulley 180, over a pulley 182 on an axis common with that 7 of the pulley 179, under a pulley 183 on an axis common with that of the pulley 178, about a pulley 185, and then under a portion of the segment 177 to a point of attachment as at 186. In operation, it will be understood that when the segment 177 is rocked in a clockwise direction as viewed in FIG. 10, the cable ends 160a will be pulled toward the power unit 170 to thereby retract the pusher carrying the pusher pawls 120. Conversely, when the segment 177 is rocked in a counterclockwise direction, the upper reaches 160]) of the pusher cables will be pulled toward the power unit 174 to thereby extend the pusher carrying the pusher pawls 120. If desired, portions of the cable 175 may be comprised of rigid links.

Referring now to FIGS. 12, 13, 14 and 15, the segment 177 to which the cable 175 is attached is carried on a rocker member 190, pivoted as at 191 and provided with a radial slot as at 1% in which a crank pin 193 is positioned. The crank pin 193 is carried at the end of a crank arm 1% carrying spring biased pawls 195. The rocker member 190 is pivotally supported on a framework 197, and the crank arm 194 is rotatable on said framework. The pawls 195 engage a ratchet Wheel or drive wheel 198 fixed on a drive shaft 199 having a drive sprocket 200 secured thereon to rotate the drive shaft. In operation, it will be understood that when the drive shaft 199 and the wheel 198 are rotated in a clockwise direction as viewed in FIG. 15, the crank arm 194 will be similarly driven so that the crank pin 193 revolves about the drive shaft 199 and moves up and down in the rocker slot 192 to thereby rock the latter and the segment 177 back and forth to reciprocate the pusher. By virtue of the arrangement shown, the pusher is retracted more rapidly than it is extended.

The sprocket 290 is connected by a chain 202 (FIG. 2) to the output shaft 263 of a drive motor 204 suitably mounted on the framework 197. While the circuits for controlling the drive motor have not been illustrated herein, it will be understood that although the drive motor is mounted on the rearmost bleacher frame in a position which is not conveniently accessible each time the bleacher is to be extended or retracted, a suitable control panel may be located in a conveniently accessible position for remote control of bleacher operation.

According to the prevent invention, the drive motor 204 together with the chain 202, the sprocket 200 and the drive shaft 199, all driving the rocker member 190 to provide for extension of the bleacher frames, are also utilized for folding the bleacher; for this purpose, the drive shaft 199, which is mounted in bearings as at 206 on the framework 197, also carries a second ratchet wheel or drive wheel 210 having teeth or notches oppositely disposed relative to the teeth on the wheel 198 and engageable with yieldably mounted pawls 211 carried on the hub of a windup drum 212 having a plurality of grooves, as at 213 for receiving cables in a system for folding the bleacher.

Referring again to FIG. 2, the cable system for folding the bleacher includes a plurality of cables, four as illustrated in FIG. 2 at 226, although three cables may be utilized if desired, or even more if this is found to be necessary or desirable. Forward ends of the cables 22% are connected respectively to brackets as at 221 secured to the underside of the frontrnost footboard 53. The cable ends are preferably attached to the lower ends of depend ing arms on the brackets 221, so that when the cables are pulled rearwardly the brackets cause pivotal movement of the footboard 53 in a clockwise direction to break the frontmost bleacher linkage. The cables extend rearwardly from the brackets 221 over pulley guide systems as at 22-2 on rearwardly disposed frames and then to guide pulleys as at 224 on a beam 225 secured to the uprights 20 of the stationary rearmost frame. From the guide pulleys 224, the cables 220 extend toward the power unit 170 and over guide pulleys as at 230 and then to the winding drum 212, to which the ends of the cable are attached. By virtue of the oppositely directed teeth on the drive wheel 210, as

compared to the teeth of the drive wheel 198, when the drive motor and the drive sprocket are driven reversely relative to the direction of drive for extending the bleacher, the winding drum is rotated in a direction to wind the cables 220, drawing the frontmost bleacher frame rearwardly toward the stationary frame, and with it, the intervening frames to retracted positions.

In operation, once bleacher extension is initiated, it is desirable that extension continue until the entire bleacher is unfolded, in order to prevent stopping of the drive motor or reversal of the drive motor at a period during the operation of the pusher when a jam may occur if retraction is initiated. Accordingly, it is preferable to provide a limit switch mechanism in circuit with the motor to insure that extension is completed once it is begun and to insure that folding is completed once it is begun. To this end, a toggle switch 235 (FIG. 5a) is mounted on one of the pusher units, the unit Hltib as illustrated, and includes a switch actuating member 236 disposed in a groove 237 of a plunger 238 having opposite ends 238a and 238i; engageable respectively by brackets as at 239 and 240 secured respectively to the angle irons 22 of appropriate upright frames. In this manner, when the bleacher is fully retracted, the bracket 249 strikes the plunger end 23811 to shift the plunger rearwardly to a position at which the switch 235 is operated to permit only bleacher extension. The switch remains in this position until such time as the bleacher is fully extended, whereupon the bracket 239 engages the opposite end 238a of the plunger to actuate the switch 235 to a position wherein only bleacher retraction is permitted.

Advantages of the remotely controllable power operated mechanism described hereinabove will be apparent. Among these, it should be noted that a standard size pusher unit may be utilized for bleachers of varying numbers of rows, this particularly by virtue of the adjustability of the stationary outwardly turned channel members on the stationary supporting bar 105. Further, a stable unfolding operation is assured with the use of at least two pusher units at laterally spaced and balanced positions so that there is no tendency of the bleacher to twist and bind as may occur where a single pusher is used at a centrally located position. Additionally, pusher units of the type described may be readily installed on existing bleacher constructions as well as being incorporated in new manufactures. One drive motor powers each of the separate pusher units and also is utilized for folding the bleacher. Positive opening of each bleacher row relative to the adjacent row is assured by virtue of the trapping of a succeeding row while the preceding row is extended; thus the several rows are extended in sequence. The mechanism assures that the bleacher is locked when fully extended and locked when fully retracted, without the need for addi tional latching means. The relatively small bulk of the individual pusher units enables great flexibility in locating the units properly for installations requiring a plurality of pushers.

I claim:

1. In an extensible spectator supporting structure, a series of upright frames adapted to be supported on a floor or the like including a stationary frame at one extreme of the series, means connecting adjacent frames and permitting individual movement of all except the stationary frame between retracted positions adjacent each other and extended positions relative to the stationary frame, means for locking said connecting means in extended positions, and means for moving the movable frames from retracted positions to extended positions, comprising, a pusher disposed adjacent the frames and reciprocable toward and away from the stationary frame between a retracted position and an extended position, a pawl mounted on the pusher for movement between a position to engage successive movable frames to push the latter toward extended positions when the pusher moves toward extended position and a position to bypass succeeding 9 frames on movement of the pusher toward the stationary frame, and means connected to the pawl for moving it toward frame engaging position.

2. In an extensible spectator supporting structure, a series of upright frames adapted to be supported on a floor or the like including a stationary frame at one extreme of the series, means connecting adjacent frames and permitting individual movement of all except the stationary frame between retracted positions and extended positions relative to the stationary frame, means for locking said connecting means in extended positions, and means for moving the movable frames from retracted positions to extended positions, comprising, stationary guide means adjacent the stationary frame, a pusher reciprocable on the guide means toward and away from the stationary frame, pusher pawl mounted on the pusher for movement between a position to engage successive movable frames to push the latter toward extended positions on movement of the pusher away from the stationary frame and a position to bypass succeeding frames on movement of the pusher toward the stationary frame, means connected to the pawl for moving it toward frame engaging position, and yieldable holding means on the guide means positioned to be engageable with successive frames to hold the latter against extension While a preceding frame is extended.

3. In a foldable spectator seating structure, a series of upright frames including a stationary rearmost frame and movable frames disposed forwardly thereof adapted to be supported on a floor or the like, each of said movable frames including laterally spaced uprights and a connecting cross piece, means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions and extended positions relative to the stationary frame, means for locking said connecting means in extended positions, and means for moving the movable frames from retracted positions to extended positions, comprising, stationary guide means adjacent the stationary frame, a pusher reciprocably mounted on the guide means for movement toward and away from the stationary frame between retracted and extended positions, a pawl pivoted on the pusher and movable between a lower position enabling passage thereof beneath said frame crosspiece on retraction of the pusher and an upper position enabling contact with successive crosspieces in front to rear order on extension of the pusher to push successive frames to extended positions as the pusher is reciprocated back and forth, means on the pusher engaging and yieldably urging the pawl toward the upper position, and means connected with the pusher for reciprocating the pusher.

4. The combination as defined in claim 3, including a plate on said stationary guide means positioned to be engageable by said pawl when the pusher is completely retracted to depress the pawl to the lower position, thereby to enable movement of the frames to retracted posi tions.

5. The combination as defined in claim 3, including a holding pawl pivoted on the stationary guide means and movable between an upper position to engage said crosspieces and block movement of succeeding frames to extended positions and a depressed position enabling movement of a succeeding frame to extended position; means on the guide engaging and yieldably urging the holding pawl toward the upper position, and a plate on the pusher disposed to be engageable with the hold-ing pawl when the pusher is retracted to depress the pawl.

6. The combination as defined in claim 5, including a trap pawl pivoted on the stationary guide means adjacent the holding pawl and movable between a depressed position enabling passage of said frame crosspieces in movement toward extended and retracted positions and an upper position to engage a crosspiece also engaging the holding pawl thereby to trap said last mentioned crosspiece between the holding pawl and the trap pawl and 10 prevent movement of the trapped crosspiece toward a retracted position when the pusher is being retracted, and means on the guide engaging means yieldably urging the trap pawl toward the upper position.

7. The combination defined in claim 6, including a trap pawl release dog pivoted on the stationary guide means positioned to be engageable by a retracting crosspiece, and engageable with said trap pawl to depress the latter and allow passage of the retracting crosspiece.

8. The combination as defined in claim 3, wherein the means for reciprocating the pusher, comprises, a pulley rotatable on the stationary guide means, a cable passing about the pulley and having upper and lower reaches extending toward the stationary frame, means securing one of said reaches tothe pusher at a position between the pulley and the stationary frame, so that when one of the reaches is pulled toward the stationary frame the pusher is moved in one direction and when the other reach is pulled toward the stationary frame the pusher is moved in the opposite direction, and means connected to the cable reaches for alternately pulling opposite reaches.

9. In a foldable bleacher, a series of upright frames stepped in height upwardly from a frontmost frame to a stationary rearmost frame, each frame including laterally spaced uprights adapted to be supported on a floor or the like and a connecting crosspiece, folding linkage means connecting adjacent frames and permitting individual movement of all except the rearmost between retracted positions wherein forwardly disposed frames are positioned adjacent the next adjacent rearwardly disposed frame and the linkage means are folded and extended positions wherein the frames are spaced from each other and the respective linkage means are extended and locked, a pair of laterally spaced floor engaging pusher units for moving the frames from retracted positions to extended posit-ions, each comprising, a stationary guide mounted on the crosspiece of the rearmost frame, a pusher having floor engaging rollers, means mounting the pusher on said guide for reciprocable movement forwardly and rearwardly, a pusher pawl on the pusher disposed to be engageable with the crosspieces of successive frames on forward strokes of the pusher as the latter is reciprocated thereby to first push the frontmost frame to extended position and then to successively push succeeding rearwardly disposed frames to extended positions while pushing extended frames further forwardly, means mounting the pusher pawl movably on the pusher to pass beneath successive rearwardly disposed crosspieces on rearward strokes of the pusher, means resiliently urging the pawl toward crosspiece engaging position, holding means yieldably mounted on said guide in position for holding a succeeding crosspiece in position for engagement by said pusher pawl, a cable having a midportion secured to said pusher, guide means positioning opposite end portions of the cable so that when pulled in opposite directions the pusher is reciprocated, a rocker member, means connecting opposite ends of the cable to the rocker member to pull the cable alternately in opposite directions as the member is rocked back and forth, and means engaging the rocker member for rocking the same.

10. The combination as defined in claim 9, including a cable having one end connected to the frontmost frame for retracting the bleacher frames, a windup drum having the opposite end of the last mentioned cable secured thereto for winding up the cable to retract the frames, and cable guide means on the bleacher frames intermediate the opposite cable ends.

11. In an extensible spectator seating structure, a series of upright frames including a stationary rearmost frame and movable frames disposed forwardly thereof adapted to be supported on a floor or the like, means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions and extended positions relative to the stationary frame, means ill for locking said connecting means in extended positions,

and means for moving the movable frames from retracted positions to extended positions, comprising, a pusher reciprocable toward and away from the stationary frame, a pawl mounted on the pusher for movement between a position to engage successive frames to push the latter to extended positions on movement of the pusher away from the stationary frame and a position to bypass succeeding frames on movement of the pusher toward the stationary frame, means connected to the pawl for moving it toward frame engaging position, and means for reciprocating the pusher, including a cable having a midportion secured to the pusher, guide means positioning opposite end portions of the cable so that when pulled alternately the pusher is reciprocated, and means connected to opposite ends of the cable for alternately pulling the cable ends.

12. The combination as defined in claim 11, wherein the last recited means comprises, a pivoted rocker member having an arcuate rim segment, means connecting opposite ends of the cable respectively to opposite ends of the segment, and means connected to the rocker member for rocking the member back and forth to alternately pull opposite ends of the cable in opposite directions.

13. The combination as defined in claim 12, wherein the last recited means comprises, a rotatable drive shaft, a ratchet fixed on the shaft, a crank arm rotatable about the axis of the drive shaft, a pawl on the crank engaging the ratchet for rotation of the arm when the drive shaft is rotated in one direction, and a crank pin on the arm engaging a slot on the rocker member to rock the latter back and forth as the crank arm is rotated.

14. In an extensible spectator seating structure, a series of upright frames adapted to be supported on a floor or the like including a stationary rearmost frame and movable frames disposed forwardly thereof, means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions and ex tended positions relative to the stationary frame, means for locking said connecting means in extended positions, and means for moving the movable frames from retracted positions to extended positions, comprising, a pusher reciprocable toward and away from the stationary frame, a pawl mounted on the pusher for movement between a position to engage successive frames to push the latter to extended positions on movement of the pusher away from the stationary frame and a position to bypass succeeding frames on movement of the pusher toward the stationary frame, means connected to the pawl for moving it toward frame engaging position, and means for reciprocating the pusher including a cable having a midportion secured to the pusher, guide means positioning opposite end portions of the cable so that when pulled alternately the pusher is reciprocated, a rocker member, means connecting opposite ends of the cable to the rocker member, a crank member having an eccentric connected to the rocker member to rock the latter as the crank member is rotated, a cable having one end connected to the frontmost frame for pulling the frames to retracted positions, a windup drum having the opposite end of the last mentioned cable secured thereto, a rotatable drive shaft, a one-way clutch connecting the drive shaft to said crank arm to rotate the latter when the drive shaft is rotated in one direction, and a one-way clutch connecting the drive shaft to the windup drum to rotate the latter when the drive shaft is rotated in the opposite direction.

15. In an extensible spectator seating structure, a series of upright frames including a stationary rearmost frame and movable frames disposed forwardly thereof adapted to be supported on a floor or the like, means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions and ex tended positions relative to the stationary frame, means for locking said connecting means in extended positions,

means for moving the movable frames from retracted 12 positions to extended positions including a pusher reciprocable toward and away from the stationary frame pawl mounted on the pusher for movement between a position to engage successive frames to push the latter to extended positions on movement of the pusher away from the stationary frame and a position to bypass succeeding frames on movement of the pusher toward the stationary frame, means connected to the pawl for moving it toward frame engaging position, a cable having one end secured to the frontmost frame for retracting the frames, a windup drum for winding the cable, and a common drive means operable alternatively to reciprocate the pusher and thereby extend the frames or rotate said drum and thereby retract said frames.

16. In an extensible spectator supporting structure, a series of upright frames including a stationarily mounted rearmost frame and movable frames disposed forwardly thereof adapted to be supported on a floor or the like, extensible means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions wherein the frames are stacked adjacent each other with the frontmost frame in a pickup position and extended positions wherein the frames are spaced from each other and the respective extensible means are extended and locked, abutment means on each of the movable frames engageable for moving the frames to extended positions, and means for moving the movable frames to extended positions in front to rear order, comprising, a mover guide stationarily mounted adjacent the stationary frame, a mover reciprocable on the guide rearwardly and forwardly relative to the stationary frame between retracted and extended positions, a mover member on the mover at a position to engage said abutment means on the frontmost frame adjacent said pickup position when the mover is retracted so that extension of the mover extends the frontmost frame, extension of each forwardly disposed frame drawing the next rearwardly disposed frame forwardly toward pickup position so that the mover member, on successive retraction and extension, engages successive abutment means to extend successive frames in front to rear order, means movably mounting the mover member on the mover to pass the abutment means on the frame in pickup position during retraction of the mover, and means yieldably urging the mover member to abutment engaging position.

17. The combination of claim 16, including a holding member yieldably mounted on said guide and engageable with successive rearwardly disposed movable frames to hold each such frame against forward movement beyond pickup position during extension of the next forward frame, and means on said mover for disabling the holding member while the moving member moves each frame forward from pickup position.

18. The combination of claim 17, including a trap member on said guide and engageable with successive rearwardly disposed frames to hold such frames against rearward movement from pickup position during retraction of the mover, and means mounting the trap member to yield on movement of each frame forwardly to pickup position.

19. In an extensible spectator supporting structure, a series of upright frames including a stationarily mounted rearmost frame and movable frames disposed forwardly thereof and adapted to be supported on a floor or the like, extensible means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions wherein the frames are stacked adjacent each other with the frontmost frame in a pickup position and extended positions wherein the frames are spaced from each other and the respective extensible means are extended and locked, abutment means on each of the movable frames adjacent a lower portion thereof engageable for controlling movement of such frames, and means for moving the movable frames to extended positions in front to rear order, comprising, a guide stationarily mounted adjacent the stationary frame beneath the retracted frame positions, a pusher reciprocable on the guide rearwardly and forwardly relative to the stationary frame between retracted and extended positions, a pawl on the pusher at a position to engage the abutment means on the frontmost frame adjacent said pickup position when the pusher is retracted so that extension of the pusher extends the frontmost frame, extension of each forwardly disposed frame drawing the next rearwardly disposed frame forwardly toward pickup position so that the pawl on successive retraction and extension engages the abutment means on successive frames to extend the frames in front to rear order, means movably mounting the pawl on the pusher to pass the abutment means on the frame in pickup position during retraction of the pusher, spring means for moving the pawl to abutment engaging position yieldable trap means on said guide engageable with said abutment means on successive rearwardly disposed movable frames and automatically operated to first admit said abutment means into the trap means with the associated frame in pickup position, then hold such frame in pickup position against forward and rearward movement therefrom during extension of the next forward frame and subsequent retraction of the pusher, and then release such frame for movement forwardly to extended position, and means for reciprocating the pusher.

20. In an extensible spectator supporting structure, a series of upright frames including a stationarily mounted rearmost frame and movable frames disposed forwardly thereof adapted to be supported on a floor or the like, foldable linkage means connecting adjacent frames and permitting individual movement of the movable frames between retracted positions wherein the linkage means are folded and the frontmost frame is in a pickup position and extended positions wherein the linkage means are extended and locked, abutment means on each of the movable frames engageable for moving the frames to extended positions, and means for moving the movable frames to extended positions in front to rear order, comprising, a guide stationarily mounted adjacent the stationary frame, a pusher reciprocable on the guide rearwardly and forwardly relative to the stationary frame between retracted and extended positions, a pawl on the pusher disposed to engage said abutment means on the frontmost frame adjacent said pickup position when the pusher is retracted so that extension of the pusher extends the frontmost frame to lock the frontmost linkage means, extension of each forwardly disposed frame drawing the next rearwardly disposed frame forwardly toward pickup position so that the pawl on successive retraction and extension engages successive abutment means to extend successive frames while positioning extended frames further forwardly, means movably mounting the pawl on the pusher to pass the abutment means on the frame in pickup position during retraction of the pusher, and means resiliently urging the pawl to abutment engaging position.

No references cited. 

1. IN AN EXTENSIBLE SPECTATOR SUPPORTING STRUCTURE, A SERIES OF UPRIGHT FRAMES ADAPTED TO BE SUPPORTED ON A FLOOR OR THE LIKE INCLUDING A STATIONARY FRAME AT ONE EXTREME OF THE SERIES, MEANS CONNECTING ADJACENT FRAMES AND PERMITTING INDIVIDUAL MOVEMENT OF ALL EXCEPT THE STATIONARY FRAME BETWEEN RETRACTED POSITIONS ADJACENT EACH OTHER AND EXTENDED POSITIONS RELATIVE TO THE STATIONARY FRAME, MEANS FOR LOCKING SAID CONNECTING MEANS IN EXTENDED POSITIONS, AND MEANS FOR MOVING THE MOVABLE FRAMES FROM RETRACTED POSITIONS TO EXTENDED POSITIONS, COMPRISING, A PUSHER DISPOSED ADJACENT THE FRAMES AND RECIPROCABLE TOWARD AND AWAY FROM THE STATIONARY FRAME BETWEEN A RETRACTED POSITION AND AN EXTENDED POSITION, A PAWL MOUNTED ON THE PUSHER FOR MOVEMENT BETWEEN A POSITION TO ENGAGE SUCCESSIVE MOVABLE FRAMES TO PUSH THE LATTER TOWARD EXTENDED POSITIONS WHEN THE PUSHER MOVES TOWARD EXTENDED POSITION AND A POSITION TO BYPASS SUCCEEDING FRAMES ON MOVEMENT OF THE PUSHER TOWARD THE STATIONARY FRAME, AND MEANS CONNECTED TO THE PAWL FOR MOVING IT TOWARD FRAME ENGAGING POSITION. 